3.2.3a Converging and diverging lenses

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Question 12

An experiment is set up to determine the focal length $f\,$ of a converging lens using an illuminated object, a lens, and a screen.

Describe a technique for obtaining an image on the screen that is as sharp as possible.

[1]

The height of the illuminated object is $cmh_O = 3.0\text{ cm}$ . When the object distance $u\,$ is set to a certain value, the height of the sharp image on the screen is measured to be $cmh_I = 4.8\text{ cm}$ . Calculate the value of $W\,$ using the formula:

\frac{h_O}{h_I}

Give your answer to 2 decimal places.

[2]

The experiment is repeated for several different object distances $u$ . A graph of $cmu\text{ / cm}$ (y-axis) against $W$ (x-axis) is plotted. The student identifies two points on the resulting line of best fit: $24.0\text{ cm})$ and $60.0\text{ cm})$ . Determine the gradient $G\,$ of this line. Show your working.

[2]

The focal length $f\,$ of the lens is numerically equal to the gradient $G$ . State the value of $f\,$ in $cm\text{cm}$ .

[1]

The student decides to continue the experiment using much larger values of $u$ . Explain why this produces less accurate values for $W$ .

[2]

3.2.3a Converging and diverging lenses

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Question 12

An experiment is set up to determine the focal length $f\,$ of a converging lens using an illuminated object, a lens, and a screen.

Describe a technique for obtaining an image on the screen that is as sharp as possible.

[1]

\frac{h_O}{h_I}

Give your answer to 2 decimal places.

[2]

The focal length $f\,$ of the lens is numerically equal to the gradient $G$ . State the value of $f\,$ in $cm\text{cm}$ .

[1]

The student decides to continue the experiment using much larger values of $u$ . Explain why this produces less accurate values for $W$ .

[2]

3.2.3a Converging and diverging lenses

Question 12

Markscheme

3.2.3a Converging and diverging lenses

Question 12

Markscheme

3.2.3a Converging and diverging lenses

Question 12

3.2.3a Converging and diverging lenses Questions

3.2.3a Converging and diverging lenses

Question 12

3.2.3a Converging and diverging lenses Questions